Adding up positive values in first negative amount

[Pinang]

Hi,

I need formula to add up positive value in first negative line in each unique projects, refer attached file for example and result.

Thanks in advance.

 

[bosco_yip]

Try,

In C2, formula copied down :

=IF(B2>0,0,SUM(B2:IF(B3<=0,B2,INDEX(B3:B$15,INDEX(MATCH(1,0/(B3:B$15>0)/(A3:A$15=A2)),0),0))))